题目链接：传送门
题解：分块

//by sdfzchy
#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
using namespace std;
typedef long long LL;
const int inf=(1<<30),N=100010,mod=1e9+7;
int n,m;
inline int in()
{
    char tmp=getchar();
    int res=0,f=1;
    while((tmp<'0'||tmp>'9')&&tmp!='-')tmp=getchar();
    if(tmp=='-') f=-1,tmp=getchar();
    while(tmp>='0'&&tmp<='9')   res=(res<<1)+(res<<3)+(tmp^48),tmp=getchar();
    return res*f;
}
int pre[N],head[N],siz,a[N],bel[N];
vector<int> v[N];
char s[10];

int ask(int l,int r)
{
    int ans=0;
    for(int i=l;i<=min(r,bel[l]*siz);i++) if(pre[i]<l)               ans++;
    if(bel[l]==bel[r]) return ans;
    for(int i=(bel[r]-1)*siz+1;i<=r;i++)  if(pre[i]<l) ans++;
    for(int i=bel[l]+1;i<=bel[r]-1;i++)   ans+=lower_bound(v[i].begin(),v[i].end(),l)-v[i].begin();
    return ans; 
}
int b[N];

void reset(int x)
{
    v[x].clear();
    for(int i=(x-1)*siz+1;i<=min(n,x*siz);i++) v[x].push_back(b[i]);
    sort(v[x].begin(),v[x].end());
}

void change(int pos,int x)
{
    memset(head,0,sizeof(head));
    a[pos]=x;
    for(int i=1;i<=n;i++)
    {
        b[i]=head[a[i]];
        head[a[i]]=i;
    }
    for(int i=1;i<=n;i++)
        if(pre[i]!=b[i])
            reset(bel[i]),i=bel[i]*siz;
    for(int i=1;i<=n;i++) pre[i]=b[i],b[i]=0;
}

int main()
{
    n=in(),m=in();siz=sqrt(n);
    for(int i=1;i<=n;i++)
    {
        a[i]=in();
        pre[i]=head[a[i]];
        head[a[i]]=i;
        bel[i]=(i-1)/siz+1;
        v[bel[i]].push_back(pre[i]);
    }
    for(int i=1;i<=bel[n];i++) sort(v[i].begin(),v[i].end());
    for(int i=1,x,y;i<=m;i++)
    {
        scanf("%s",s);x=in(),y=in();
        if(s[0]=='Q') printf("%d\n",ask(x,y));
        else change(x,y);
    }
    return 0;   
}